Myosin-1c (Myo1c) is essential to the mechanosensitive process of slow adaptation that occurs during transduction in hair cells, the sensory receptor cells of the inner ear. Previous data, using T701, a protein fragment consisting of Myo1c neck and tail domains, has shown that Myo1c interacts with other components of the transduction complex, termed "receptors," through its neck domain. This domain is also known to interact with calmodulin (CaM), and excess CaM has been shown to disrupt Myo1c interactions with receptors. Myo1c has also been shown to interact, in a tissue culture cell line, with cadherin 23 (Cdh23), a cell-adhesion protein recently shown to be part of the transduction complex. The goal of this research is to describe Myo1c's interactions with unidentified hair-cell receptors and Cdh23. To further characterize CaM's regulation of Myo1c interactions with receptors, directed mutations to the neck region of Myo1c will be made in the context of T701. In addition, identical mutations will be made in the context of full-length Myo1c and tested in ATPase and motility assays. Finally, the proposed interaction between Myo1c and Cdh23 will be explored within the context of the hair cell.